Scientists believe that they have found the strongest evidence yet to prove that the continents were created by massive meteor impacts in the Earth’s early history.
According to Curtin University researchers, meteorite impacts were “particularly common during the first billion years of our planet’s four-anda-half billion-year history”.
Although the theory that the continents formed from the impact sites has been popular for decades, Dr Tim Johnson says there is not much solid evidence.
Dr Johnson stated that “By studying tiny crystals made of the mineral zircon from rocks from the Pilbara Craton, Western Australia, which is Earth’s best-preserved relic of ancient crust, I found evidence of these huge meteorite impacts.”
Pilbara’s iron-rich mineral deposits are among the oldest on Earth. They have been previously discovered as evidence of the earliest human life on Earth.
“Studying of the composition of oxygen isotopes within these zircon crystals revealed that a top-down process began with the melting of rocks near surface and continued deeper, consistent with giant meteorite impact geological effects,” said Dr Johnson.
“Our research shows that the process that eventually formed the continents was initiated by giant meteorite impact, which is similar to the ones that caused the extinctions of the dinosaurs but that occurred billions of year earlier.”
Scientists explained that understanding how Earth’s continents formed and evolved is essential because of their dependence on mineral deposits.
Dr Johnson stated that “the continents host crucial metals like nickel, tin, and lithium, which are commodities that are essential for the emerging green technologies required to fulfill our obligation to reduce climate change.”
“These mineral deposits are the result of a process called crustal differentiation. It began with the formation the earliest landmasses. The Pilbara Craton is one example.
“Data from other areas of ancient crust on Earth seems to show similar patterns to those in Western Australia.” To test our models on these rocks, we would like to prove that they are more universally applicable.